I have had the same problem on and off for 30 years...can't quite figure it out. I do know that it does feel better after I warm up and usually doesn't hurt as I'm running. It also tends to switch from right to left, never both, getting better on one side the starting up a while later on the other. Lately my left has gotten really bad when I have to sit for extended periods, especially in the car....but doesn't hurt to run.
Pretty much have tried everything but would be glad to hear about anything you come up with.
Thanks for sharing your experience. Yes, I know that pain bc I had it too for many years in my late 30s and all through the 40s. Especially when driving for a while! When I started with teaching yoga the pain went away which made me think that I really needed to stretch all the chain-muscles from the calves up-hamstrings-butt and back.
So I haven't had a pain (in the butt) for a long while. Now, this really IS an injury as I felt it bc I made a step and the ground was lower than my foot had anticipated and it immediately hurt my hamstring. I hope with a little rest together with easy stretches when I'm painfree, I'll be able to heal it again. But age is not on my side as tendons and ligaments tend to lose their elasticity and those kinds of injuries (everywhere) are popping up faster such as in the shoulder, legs, elbows, etc.
Good luck with with your hamstrings (thinking that both your hamstrings hurt, it must come from tight back-butt-leg muscles and doing "downward facing dogs" (yoga pose, doing it correctly might help when done regularly). :-))
Auguri, Beatrice, e spera che tu guarisca prestissimo.
As you are well aware, stretching and strengthening will slowly repair this sort of thing. You have the knowledge and the discipline. I hope you will be running pain free soon.